/******************************************************************************

Copyright (c) 2010, Cormac Flanagan (University of California, Santa Cruz)
                    and Stephen Freund (Williams College) 

All rights reserved.  

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the names of the University of California, Santa Cruz
      and Williams College nor the names of its contributors may be
      used to endorse or promote products derived from this software
      without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

******************************************************************************/

// based on ASM code

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.  
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package rr.instrument.analysis;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.signature.SignatureVisitor;

/**
 * A {@link SignatureVisitor} that prints a disassembled view of the desc
 * it visits.
 * 
 * @author Eugene Kuleshov
 * @author Eric Bruneton
 */
public class TraceSignatureVisitor implements SignatureVisitor {

    private StringBuffer declaration;

    private boolean isInterface;

    private boolean seenFormalParameter;

    private boolean seenInterfaceBound;

    private boolean seenParameter;

    private boolean seenInterface;

    private StringBuffer returnType;

    private StringBuffer exceptions;

    /**
     * Stack used to keep track of class types that have arguments. Each element
     * of this stack is a boolean encoded in one bit. The top of the stack is
     * the lowest order bit. Pushing false = *2, pushing true = *2+1, popping =
     * /2.
     */
    private int argumentStack;

    /**
     * Stack used to keep track of target class types. Each element of this stack
     * is a boolean encoded in one bit. The top of the stack is the lowest order
     * bit. Pushing false = *2, pushing true = *2+1, popping = /2.
     */
    private int arrayStack;

    private String separator = "";

    public TraceSignatureVisitor(final int access) {
        isInterface = (access & Opcodes.ACC_INTERFACE) != 0;
        this.declaration = new StringBuffer();
    }

    private TraceSignatureVisitor(final StringBuffer buf) {
        this.declaration = buf;
    }

    public void visitFormalTypeParameter(final String name) {
        declaration.append(seenFormalParameter ? ", " : "<").append(name);
        seenFormalParameter = true;
        seenInterfaceBound = false;
    }

    public SignatureVisitor visitClassBound() {
        separator = " extends ";
        startType();
        return this;
    }

    public SignatureVisitor visitInterfaceBound() {
        separator = seenInterfaceBound ? ", " : " extends ";
        seenInterfaceBound = true;
        startType();
        return this;
    }

    public SignatureVisitor visitSuperclass() {
        endFormals();
        separator = " extends ";
        startType();
        return this;
    }

    public SignatureVisitor visitInterface() {
        separator = seenInterface ? ", " : isInterface
                ? " extends "
                : " implements ";
        seenInterface = true;
        startType();
        return this;
    }

    public SignatureVisitor visitParameterType() {
        endFormals();
        if (!seenParameter) {
            seenParameter = true;
            declaration.append('(');
        } else {
            declaration.append(", ");
        }
        startType();
        return this;
    }

    public SignatureVisitor visitReturnType() {
        endFormals();
        if (!seenParameter) {
            declaration.append('(');
        } else {
            seenParameter = false;
        }
        declaration.append(')');
        returnType = new StringBuffer();
        return new TraceSignatureVisitor(returnType);
    }

    public SignatureVisitor visitExceptionType() {
        if (exceptions == null) {
            exceptions = new StringBuffer();
        } else {
            exceptions.append(", ");
        }
        // startType();
        return new TraceSignatureVisitor(exceptions);
    }

    public void visitBaseType(final char descriptor) {
        switch (descriptor) {
            case 'V':
                declaration.append("void");
                break;
            case 'B':
                declaration.append("byte");
                break;
            case 'J':
                declaration.append("long");
                break;
            case 'Z':
                declaration.append("boolean");
                break;
            case 'I':
                declaration.append("int");
                break;
            case 'S':
                declaration.append("short");
                break;
            case 'C':
                declaration.append("char");
                break;
            case 'F':
                declaration.append("float");
                break;
            // case 'D':
            default:
                declaration.append("double");
                break;
        }
        endType();
    }

    public void visitTypeVariable(final String name) {
        declaration.append(name);
        endType();
    }

    public SignatureVisitor visitArrayType() {
        startType();
        arrayStack |= 1;
        return this;
    }

    public void visitClassType(final String name) {
        if (!"java/lang/Object".equals(name)) {
            declaration.append(separator).append(name.replace('/', '.'));
        } else {
            // Map<java.lang.Object,java.util.List>
            // or
            // abstract public V get(Object key); (seen in Dictionary.class)
            // should have Object
            // but java.lang.String extends java.lang.Object is unnecessary
            boolean needObjectClass = argumentStack % 2 != 0 || seenParameter;
            if (needObjectClass) {
                declaration.append(separator).append(name.replace('/', '.'));
            }
        }
        separator = "";
        argumentStack *= 2;
    }

    public void visitInnerClassType(final String name) {
        if (argumentStack % 2 != 0) {
            declaration.append('>');
        }
        argumentStack /= 2;
        declaration.append('.');
        declaration.append(separator).append(name.replace('/', '.'));
        separator = "";
        argumentStack *= 2;
    }

    public void visitTypeArgument() {
        if (argumentStack % 2 == 0) {
            ++argumentStack;
            declaration.append('<');
        } else {
            declaration.append(", ");
        }
        declaration.append('?');
    }

    public SignatureVisitor visitTypeArgument(final char tag) {
        if (argumentStack % 2 == 0) {
            ++argumentStack;
            declaration.append('<');
        } else {
            declaration.append(", ");
        }

        if (tag == SignatureVisitor.EXTENDS) {
            declaration.append("? extends ");
        } else if (tag == SignatureVisitor.SUPER) {
            declaration.append("? super ");
        }

        startType();
        return this;
    }

    public void visitEnd() {
        if (argumentStack % 2 != 0) {
            declaration.append('>');
        }
        argumentStack /= 2;
        endType();
    }

    public String getDeclaration() {
        return declaration.toString();
    }

    public String getReturnType() {
        return returnType == null ? null : returnType.toString();
    }

    public String getExceptions() {
        return exceptions == null ? null : exceptions.toString();
    }

    // -----------------------------------------------

    private void endFormals() {
        if (seenFormalParameter) {
            declaration.append('>');
            seenFormalParameter = false;
        }
    }

    private void startType() {
        arrayStack *= 2;
    }

    private void endType() {
        if (arrayStack % 2 != 0) {
            while (arrayStack % 2 != 0) {
                arrayStack /= 2;
                declaration.append("[]");
            }
        } else {
            arrayStack /= 2;
        }
    }
}
